All Blacks coach Steve Hansen has reopened a war of words with Lions counterpart Warren Gatland.

Hansen has taken a swipe at his compatriot for claiming he "hated" the British and Irish Lions tour this summer and told him if that was the case, he should get out of coaching.

Gatland led the Lions to a dramatic 1-1 series draw but the New Zealander has since told British media that he hated the tour, the local media and the "negativity" in his homeland.

Criticism from players like Ireland flanker Sean O'Brien and England loose forward Billy Vunipola, who withdrew from the squad due to injury, had also convinced Gatland not to be involved with the Lions again.

"I've only just heard it (Gatland's comments) because I don't read too much about what coaches are saying and doing," Hansen told New Zealand's Radio Sport.

"Why would you hate coaching the Lions? If you hate coaching, don't do it. I love coaching any team I've been involved in - that's the reason I'm doing it.

"I'm lucky enough to coach the All Blacks, which is fantastic, if you are lucky enough to coach the Lions it is also fantastic."

Hansen added the scrutiny that Gatland said he encountered was the same he would receive if he ever got the opportunity to coach the All Blacks and would need to learn to deal with it.

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Gatland's contract with Wales ends after the 2019 Rugby World Cup in Japan and he has been tipped as a potential candidate to replace Hansen, who is contracted until early 2020.

"Welcome to our world," Hansen said. "You are under constant pressure, constant scrutiny. People expect you to be able to front up and do the job well.

"In the All Blacks' case, we are expected to win every test match and win it well.

"You don't want to change those expectations - they drive your own inner expectations to be even higher. It drives that necessity to want to always be better."

The All Blacks leave on Friday for their end-of-season tour to Europe, which ends with a test against Gatland's Wales.

While Hansen's team were unbeaten in the Rugby Championship, they have been enigmatic this season and have already lost two matches in the same year for the first time since he took control in 2012.

Hansen, however, said he expected the team to rebound next year with the experience gained by several fringe players and that the side would be aided by the return of several players from long-term injuries.

"We've got some trying circumstances at the moment with nine or 10 players out. That's on top of losing all that legendary talent after the World Cup - that's over 50 percent of your team," he said.

"It is a heck of a great challenge for us to come through, but next year when all nine are available then watch what happens because we've grown depth and experience."